Aim: The evaluation of venous structures using color doppler ultrasonography (CDUS) has a distinctive place in both diagnosis and treatment. Because venous structures demonstrate a wide range of variations, it is important to have a good knowledge about these variations, to improve the diagnosis and treatment efficacy. The purpose of this study was to evaluate anatomic variations of the great saphenous vein (GSV). Material and Method: In this study, 500 GSVs of 250 patients who had applied to the radiology department of the Adana Numune Teaching and Research Hospital between July 2013 and October 2014, were examined by CDUS. 54 patients were males, and 196 were females. The age spectrum was 17 - 48 years and the mean age was 33.3 +/- 8.0 (sd). Statistical analyses were percentage ratios and standard deviations (sd). For this study, linear transducers with a frequency range of 7.5 - 13.0 MHz, were used. Results: In the study, 4 variations at the thigh level, 5 variations at the knee level and 3 variations at the leg level, were detected. All variations were described and given with their percentages. Discussion: The anatomic variations of the GSV and their frequencies were studied. Due to its simplicity, cheapness, and effectivity, CDUS has been widely preferred for the examination and evaluation of venous structures, and it has a unique place in the diagnosis of situations concerning these vessels.